1. Field of the Invention
The present invention relates to a scanning printing apparatus or a self-propelled type printing apparatus which performs printing onto a recording medium by scanning its main body provided with a printing means, and to a method of printing using the scanning printing apparatus. In particular, the present invention relates to a scanning printing apparatus capable of easily printing an image composed of a plurality of row images using an ink jet recording method, and to a method of printing using the scanning printing apparatus.
2. Description of the Related Art
Up to now, various proposals have been made for scanning printing apparatuses for printing an image onto a recording medium such as paper with manual scanning of its main body prepared with a printing means (JP 9-267522 A, JP 9-300727 A, JP 10-35029 A, JP 10-35032 A, JP 8-1096 U, and the like).
A manual scanning printing apparatus disclosed in JP 9-267522 A is a printing apparatus for printing capital letters over a plurality of row images by a plurality of scanning operations, and a dot position detecting circuit (printing position detecting means) for detecting the dot printing position of the previous row image is formed. The printing position of the dots of the row image prior to the row image to be currently printed is thus detected. Printing timing is then corrected based on a detection signal, and further, a shifting amount for character data is determined, the character data is shifted, a character pattern is set, and printing is performed.
With a manual scanning printing apparatus disclosed in JP 9-300727 A, a break point detecting means for detecting whether or not a print head printing position is in a break point position for the current character data, and an informing means which turns off a light emitting device when the printing head printing position is in the break point position for the character data (blank position between characters) are formed. After the reception of a signal from the detecting means, the light emitting device is turned on when the printing position of the print head is the character position of the current printing data. A user can thus know that the print head is currently in the blank position between characters when the light emitting device is turned off. A linefeed may thus be performed when the light emitting device is turned off, and therefore the linefeed can be accomplished easily and the character to be printed can be printed without segmentation.
Three position signal generator devices are disposed in a manual scanning printing apparatus disclosed in JP 10-35029 A, and each position signal generated from the position signal generator devices is received by a signal receiver of a main body portion. The current position of the main body portion is detected based on the phase difference in each of the position signals, data corresponding to a two-dimensional position is received, and printing is performed. The position of the main body portion can thus be accurately detected, printing operations can be accurately performed, and therefore very good printing results can be obtained.
In a manual scanning printing apparatus disclosed in JP 10-35032 A, the amount of shift with respect to the printing direction of the apparatus is detected based upon the difference in rotational speed of left and right rollers, and the printing position of a recording head is corrected based upon the amount of shift. Good printing results can thus be obtained even if there are no guides, such as ruled lines, on the recording medium.
A manual scanning printing apparatus disclosed in JP 8-1096 U has a movable housing, a print head is formed within the movable housing, and a printing surface of the print head protrudes from an opening portion formed in a bottom wall portion. A rotatable spindle is formed in the bottom wall portion of the movable housing, and a pair of rollers are attached to the spindle. Further, a supplemental roller is rotatably formed in a position away from the spindle. In addition, a display lamp is provided which is turned off when a linefeed code is sent as printing data. A predetermined character pattern is formed in the print head by the printing data, and the character pattern is transferred to the surface of the recording medium by an ink donor film disposed on the print head. Further, an operator can verify that the linefeed code has been sent, and therefore whether or not printing is performed on the same row image can be appropriately selected.
However, there is a problem with these conventional techniques in that an image cannot be easily printed over a plurality of row images. Further, another problem is that manual scanning in a straight line is difficult to be performed.
In order to solve the problems with the conventional techniques, an object of the present invention is to provide a scanning printing apparatus capable of easily printing an image composed of a plurality of row images with good image quality.
Another object of the present invention is to provide a method of printing using the scanning printing apparatus.
The invention provides a scanning printing apparatus for printing an image composed of a plurality of row images, in accordance with image signals, each row image being printed while moving in one direction or its opposite direction on a recording medium, comprising: moving means for moving the scanning printing apparatus itself on the recording medium in the one direction or its opposite direction; a first ejection head for printing each row image of the image on the recording medium, having: a plurality of nozzles for ejecting ink, disposed in another direction orthogonal to the one direction; and an ink ejecting means disposed corresponding to the plurality of nozzles and modulated and driven in accordance with the image signals; a second ejection head for printing predetermined invisible marks which cannot be identified by humans on the recording medium; a first sensor for detecting the predetermined invisible marks which have been printed on the recording medium; and control means for controlling the moving means based on detection results of the first sensor.
It is preferable that the second ejection head prints an invisible straight line, which cannot be identified by humans, as the predetermined invisible marks along the one direction or its opposite direction from a side further upstream than a portion at which a region printed by the first ejection head begins; the first sensor detects position of the invisible straight line in the other direction; and the control means controls the moving means so that the position of the invisible straight line in the other direction, which is detected by the first sensor, is held within a predetermined range.
The scanning printing apparatus may further comprises a third ejection head for printing on the recording medium other predetermined invisible marks which cannot be identified by humans and which extend in the other direction and at least, further upstream in the one direction or its opposite direction than the first ejection head; and a second sensor for detecting the other predetermined invisible marks which have been printed on the recording medium by the third ejection head.
It is also preferable that the control means has determining means for determining whether a position of the first ejection head is suitable for printing or not, and the apparatus further comprising: warning generating means for generating a predetermined warning when the determining means determines based on the detection results of the first sensor, that the position of the first ejection head is not suitable for printing.
It is still also preferable that control means has determining means for determining whether a position of the first ejection head is suitable for printing or not, and the control means controls the moving means to correct the position of the first ejection head so as to be suitable for printing when the determining means determines based on the detection results of the first sensor, that the position of the first ejection head is not suitable.
The scanning printing apparatus may further comprises a storage unit for storing image signals for the image composed of the plurality of row images which is printed on the recording medium.
The invention also provides a method of printing an image composed of a plurality of row images in accordance with image signals on a recording medium by using a scanning printing apparatus having moving means for moving the scanning printing apparatus itself on the recording medium in one direction or its opposite direction, the apparatus printing each row image of the image while moving in the one direction or its opposite direction on the recording medium, comprising: printing predetermined invisible marks which cannot be identified by humans, while printing each row image of the image composed of the plurality of row images; detecting the predetermined invisible marks that have been printed in a previous row image in printing of each row image; and correcting a printing position based on a position of the thus detected invisible marks, thus aligning each row image of the plurality of row images.
It is preferable that the predetermined invisible marks are a first invisible straight line printed along the one direction or its opposite direction from further upstream than each row image; the first invisible straight line printed in printing of the previous row image is detected in printing each row image; and the printing position is controlled so that the detected position of the first invisible straight line falls within a predetermined range determined in advance, thus aligning each row image.
It is also preferable that the predetermined invisible marks are a first invisible straight line printed along the one direction or its opposite direction from further upstream than each row image; the first invisible straight line is detected by a sensor immediately after printing in printing each row image; and the printing position is corrected so that the detected position of the first invisible straight line falls within a predetermined range determined in advance, thus performing control such that the printing direction of each row image is along with the one direction or its opposite direction.
The method may further comprise: printing a second invisible straight line, which cannot be identified by humans, as the predetermined invisible marks along other direction orthogonal to the one direction or its opposite direction and upstream from each row image in the one direction or its opposite direction, and determining a starting position for printing of each row image by detecting the second invisible straight line printed in printing the previous row image by using a sensor in printing each row image.
It is also preferable that a warning is issued that the printing position of the scanning printing apparatus is not suitable when the detected position of the predetermined invisible marks is outside of a predetermined range in printing each row image.
It is still also preferable that printing of the row image being printed is stopped when the detected position of the predetermined invisible marks is outside of a predetermined range in printing each row image.